And next here tonight, the hunt for a family of ma readers is under way, a protective mother bear and her two cubs. A man came face-to-face with one last week and his dog is the reason he's still alive. What we're learning about how man and dog escaped with their lives. Here's ABC's Mara schiavocampo. Reporter: They can weigh up to 600 pounds and run up to 35 miles per hour. Naes exactly what Steve Kirchbaum and his dog Henry found themselves staring down in West Virginia last week. I hear this crack over to the left and I look over there and I see these two small cubs, maybe 30 pounds apiece. Reporter: Henry wasn't on a leash, and mama bear attacked Kirchbaum. She charged down the bank and bit my thigh and knocked me to the ground. Reporter: That's when Henry sprang into the action, attacking the bear, giving Kirchbaum time to pick up a rock and fight her off. I was able to pick up this rock. Reporter: They walked three quarters of a mile to the car and drove to a nearby market for help. A bear attacked him. He's bleeding profusely. They said he could pass out. He said he's cut up really bad. Where is he bleeding from? He's bleeding from his legs and his torso, arms. Reporter: Kirchbaum and Henry will be okay. Experts say black bear attacks are extremely rare. If you do come across one, what should you do? Well, the best thing to do is just give the bear its space. You want to back away slowly and talk in a calm voice so the bear knows you're not a threat and you can both go on your way. Reporter: And as one hiker recently learned, keep your dog on a leash. When we come back, the

This transcript has been automatically generated and may not be 100% accurate.

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